1. Field of the Disclosure
The disclosure relates to a control device for an internal combustion engine and, in particular, relates to a control device suitable for controlling an internal combustion engine mounted on a vehicle.
2. Description of Related Art
Japanese Patent Application Publication No. 2001-304028 (JP 2001-304028 A) discloses an internal combustion engine having both a function of retarding an ignition crank angle according to the knock intensity and a function of decreasing a target value of cooling water temperature according to the knock intensity. It is known that, in an internal combustion engine, as the ignition crank angle is more retarded, knocking is more difficult to occur while fuel consumption is deteriorated. It is also known that as the cooling water temperature decreases, the in-cylinder temperature decreases so that knocking is more difficult to occur.
When knocking has occurred in the above-mentioned conventional internal combustion engine, a state in which knocking is difficult to occur is created by both the retard of the ignition crank angle and the decrease in the cooling water temperature. In this case, compared to a case where knocking is prevented relying only on the retard of the ignition crank angle, it is possible to suppress the retard amount of the ignition crank angle necessary for such knocking prevention. Therefore, according to the above-mentioned conventional internal combustion engine, the occurrence of knocking can be properly prevented without excessively retarding the ignition crank angle and thus without largely deteriorating the fuel consumption.